Kinetic insights into agonist-dependent signalling bias at the pro-inflammatory G-protein coupled receptor GPR84.
Vincent B Luscombe, Luis Alberto Baena-L��pez, Carole J R Bataille, Angela J Russell, David R Greaves
Author Information
Vincent B Luscombe: Sir William Dunn School of Pathology, South Parks Rd, University of Oxford, Oxford, Oxfordshire, OX1 3RE, United Kingdom.
Luis Alberto Baena-L��pez: Sir William Dunn School of Pathology, South Parks Rd, University of Oxford, Oxford, Oxfordshire, OX1 3RE, United Kingdom.
Carole J R Bataille: Department of Chemistry, Mansfield Rd, University of Oxford, Oxford, Oxfordshire, OX1 3TA, United Kingdom.
Angela J Russell: Department of Chemistry, Mansfield Rd, University of Oxford, Oxford, Oxfordshire, OX1 3TA, United Kingdom; Department of Pharmacology, Mansfield Rd, University of Oxford, Oxford, Oxfordshire, OX1 3TA, United Kingdom.
David R Greaves: Sir William Dunn School of Pathology, South Parks Rd, University of Oxford, Oxford, Oxfordshire, OX1 3RE, United Kingdom. Electronic address: david.greaves@path.ox.ac.uk.
GPR84 is an orphan G-protein coupled receptor (GPCR) linked to inflammation. Strategies targeting GPR84 to prevent excessive inflammation in disease are hampered by a lack of understanding of its precise functional role. We have developed heterologous cell lines with low GPR84 expression levels that phenocopy the response of primary cells in a label-free cell electrical impedance (CEI) sensing system that measures cell morphology and adhesion. We then investigated the signalling profile and membrane localisation of GPR84 upon treatment with 6-OAU and DL-175, two agonists known to differentially influence immune cell function. When compared to 6-OAU, DL-175 was found to exhibit a delayed impedance response, a delayed and suppressed activation of Akt, which together correlated with an impaired ability to internalise GPR84 from the plasma membrane. The signalling differences were transient and occurred only at early time points in the low expressing cell lines, highlighting the importance of receptor number and kinetic readouts when evaluating signalling bias. Our findings open new ways to understand GPR84 signalling and evaluate the effect of newly developed agonists.
